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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Brendan Gregg <brendan.d.gregg@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Alexei Starovoitov <ast@kernel.org>
Cc: mhiramat@kernel.org, Ingo Molnar <mingo@kernel.org>,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
	Daniel Borkmann <daniel@iogearbox.net>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	"David S . Miller" <davem@davemloft.net>,
	paulmck@kernel.org, joel@joelfernandes.org,
	"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Subject: [RFT PATCH 03/13] kprobes: Postpone optimizer until a bunch of probes (un)registered
Date: Thu, 16 Jan 2020 23:44:42 +0900	[thread overview]
Message-ID: <157918588172.29301.12636373067838941611.stgit@devnote2> (raw)
In-Reply-To: <157918584866.29301.6941815715391411338.stgit@devnote2>

Add a counter to kick_kprobe_optimizer() to detect any
additional register/unregister kprobes and postpone
kprobe_optimizer() until a bunch of probes are registered.

This might improve some long waiting unregistration process
for bunch of kprobes.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/kprobes.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index a2c755e79be7..0dacdcecc90f 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -465,6 +465,7 @@ static struct kprobe *get_optimized_kprobe(unsigned long addr)
 static LIST_HEAD(optimizing_list);
 static LIST_HEAD(unoptimizing_list);
 static LIST_HEAD(freeing_list);
+static int kprobe_optimizer_queue_update;
 
 static void kprobe_optimizer(struct work_struct *work);
 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
@@ -555,12 +556,22 @@ static void do_free_cleaned_kprobes(void)
 static void kick_kprobe_optimizer(void)
 {
 	schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
+	kprobe_optimizer_queue_update++;
 }
 
 /* Kprobe jump optimizer */
 static void kprobe_optimizer(struct work_struct *work)
 {
 	mutex_lock(&kprobe_mutex);
+
+	/*
+	 * If new kprobe is queued in optimized/unoptimized list while
+	 * OPTIMIZE_DELAY waiting period, wait again for a series of
+	 * probes registration/unregistrations.
+	 */
+	if (kprobe_optimizer_queue_update > 1)
+		goto end;
+
 	cpus_read_lock();
 	mutex_lock(&text_mutex);
 	/* Lock modules while optimizing kprobes */
@@ -593,6 +604,8 @@ static void kprobe_optimizer(struct work_struct *work)
 	mutex_unlock(&text_mutex);
 	cpus_read_unlock();
 
+end:
+	kprobe_optimizer_queue_update = 0;
 	/* Step 5: Kick optimizer again if needed */
 	if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
 		kick_kprobe_optimizer();


  parent reply	other threads:[~2020-01-16 14:44 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16 14:44 [RFT PATCH 00/13] tracing: kprobes: Introduce async unregistration Masami Hiramatsu
2020-01-16 14:44 ` [RFT PATCH 01/13] kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex Masami Hiramatsu
2020-01-16 14:44 ` [RFT PATCH 02/13] kprobes: Remove redundant arch_disarm_kprobe() call Masami Hiramatsu
2020-01-16 14:44 ` Masami Hiramatsu [this message]
2020-01-16 14:44 ` [RFT PATCH 04/13] kprobes: Make optimizer delay to 1 second Masami Hiramatsu
2020-01-22  0:29   ` Steven Rostedt
2020-01-22  7:23     ` Masami Hiramatsu
2020-01-22 12:11       ` Steven Rostedt
2020-01-22 13:12         ` Masami Hiramatsu
2020-01-22 16:54           ` Paul E. McKenney
2020-01-23  1:33             ` Masami Hiramatsu
2020-01-23  2:26               ` Paul E. McKenney
2020-01-23  6:13                 ` Masami Hiramatsu
2020-01-23 10:03                   ` Paul E. McKenney
2020-01-16 14:45 ` [RFT PATCH 05/13] tracing/kprobe: Use call_rcu to defer freeing event_file_link Masami Hiramatsu
2020-01-27 15:02   ` kbuild test robot
2020-01-27 15:02   ` [RFC PATCH] tracing/kprobe: trace_kprobe_disabled_finished can be static kbuild test robot
2020-01-28 15:02     ` Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 06/13] kprobes: Enable kprobe-booster with CONFIG_PREEMPT=y Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 07/13] kprobes: Use normal list traversal API if a mutex is held Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 08/13] kprobes: Use workqueue for reclaiming kprobe insn cache pages Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 09/13] kprobes: Free kprobe_insn_page asynchronously Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 10/13] kprobes: Make free_*insn_slot() mutex-less Masami Hiramatsu
2020-01-16 14:46 ` [RFT PATCH 11/13] kprobes: Add asynchronous unregistration APIs Masami Hiramatsu
2020-01-16 14:46 ` [RFT PATCH 12/13] tracing/kprobe: Free probe event asynchronously Masami Hiramatsu
2020-01-16 14:46 ` [RFT PATCH 13/13] tracing/kprobe: perf_event: Remove local kprobe " Masami Hiramatsu

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